The “Bush Look” – Real World Thoughts…November 9, 2012
Thought I would take a sec and talk some real world numbers…
The past two weeks have been busy with finishing the annual on the C170. While in annual, I took the time to transfer the some of the more extreme “bush mods” over to the new C180. As the A/C was a bit closer to stock, I was really interested in seeing how it performed.
The WX has been a bit temperamental with these hurricanes and nor-easters, but today I was able to do a bit of flying and see how the old bird performed w/out some of the (as some would say) more radical mods.
Some interesting info: (actual weights)
height lost w/ smaller tires (measured from the deck to the spinner: -4″
(BTW the C180 gear raised the A/C +2″. I had +6 overall, and now I am +2 over stock. Still better AOA)
removed ABW 8.5×10 tires and 10″ wheels. -85lbs
added 600×6 tires and Cleveland wheels +27lbs
removed ABW Baby Bush -11.5lbs
added Scott 3200 TW +8.5
removed bubble windows and installed Cessna stock windows (no change)
removed BAS harness -5
added stock lap belts +3
removed 8042 prop and installed 7655 (no change)
In “Bush” mode with climb prop, the A/C cruised at 94mph at 2450
W/ the 8042 I (if not careful) could over rev the prop. Typically climbed out not at Vy, but matching the climb to RPM and keeping it at 2700 rpm. This netted 62mph at aprox 1100 ft/min.
at 2700, Max speed indicated about 105mph to burn 5.5-6.5 gph.
W/ that stuff removed (and 7655 prop) I cruised at 105 mph at 2450
Max speed at 2700rpm was 125mph.
Climb performance suffered with the cruise prop on loosing about 500’/min, but benefited +20mph at full throttle.
testing done at 1500′ MSL at 40 degrees ambient. DA was in the minus.
Grass was DEFINITELY no where near as fun…. The pragmatists will argue this, and its totally doable and safe, but don’t let em fool you. Its jarring. All those that have said the 170 does not need anything bigger than stock for off airport are full of you know what. They have never laid out the cash and tried it with the big rubber on. W/ the biggies, the 170 operated in the rough like a caddy. W/ the girlies on, the fun is gone.
On the plus side: With the stuff removed, I can certainly feel the weight difference. The A/C is way more nimble and delicate. Not as lumbering. I can only imagine what it would be like with wheel pants. Its way easier to move around in the hanger w/ less tire resistance as well as being lighter in general. With less weight, I feel it popping off the runway a bit quicker (letting the tail up first) but shorter on the short-field TO because the AOA is a bit more shallow (A/C is much lower)
In general I will say this: It comes down to what you want to do with the airplane. If you want speed and be able to tool around your airfield, stay stock. But if you want to really have fun with your 170 rumbling on anything besides the tarmac, look into bigger shoes. You don’t have to go crazy, but the fun factor outweighs any deficit.
Personally if I had to do it all over again (and I am with the 180) I would do the exact same thing.